Results

I. Single repeats

All individuals performed significantly above chance level across all four behaviors (p-value: <0.0001). The birds performed with approximately 75% accuracy (chance level= 25%). There was no significant difference of performance between the birds (variance= 0).

II. Double repeats

All of the parrots performed above chance level across all four behaviors with a ~60% accuracy (p-value= <0.0001, chance level= 6.25%). There were small individual differences in the performance between bird of 0.153.

Figure 1. Mean Performance (±SD) of the macaws (n=8) in the control trials (blue), the single repeat trials (red), and the double repeat trials (green). The dashed lines correspond to the single repeat chance level (25%) and the double repeat chance level (6.25%) respectively

III. Delayed repeats

The probability of a correct response significantly diminished as the delay time increased (p=0.003). The birds performed significantly above chance level for up to 21 s delay (CI= 95%).

Figure 2. Performance int the delayed repeat test. The x-axis shows the delay duration in seconds and the y-axis the probability of correct repeat responses. Each data point represents one observation. The blue line represents the predicted probability of a correct response through time. The gray shaded area represents the 95% CI. The dotted line represents the chance level.

What do the results mean? How do they compare to the reported literature? I talk about it on the Discussion.

Discussion